Using DNA barcodes to track the illegal wildlife trade

Following up on our posting today about the influence of road construction on bush meat exploitation, we present a new study in which researchers test out a DNA barcode to track the illegal trade in wildlife. The research was published last week in the journal Conservation Genetics and has received some media attention.

The annual global trade in bush meat is large ($5-15 billion) with a substantial portion illegal ($5-8 billion). Past research has shown that this is contributing to the decline of many species. Laws such as the U.S. Endangered Species Act and the Convention on the International Trade of Endangered Species do restrict the exploitation and marketing of bush meat. But enforcing these laws relies on the ability to identify the wildlife being traded. This can be difficult because the bush meat is often processed to the point of being difficult or impossible to identify on sight alone. This is where genetic testing comes in handy - as an enforcement tool. The benefit of DNA barcoding is that it establishes a single genetic marker for identification across a wide number of species thus simplifying genetic testing and making it easier to enforce the law.

This study used a region of a mitochondrial gene known as COX1 primers as a standard metric. They looked at specimen from 25 commonly traded species from five taxonomic families: bovids (duikers and spiral-horned antelope), suids (red river hog), cercopithecoid primates (old world monkeys and mangabeys) alligators and crocodiles. According to the researchers, the COX1 gene is agreed upon by scientists as a viable segment of the genome to use in barcoding. The COX1 gene is a relatively small DNA segment in which mutation is rapid enough to distinguish closely related species but also slow enough that individuals within the same species have similar barcodes.

The DNA barcodes generated from the study have been added to an online, open-access repository called the Barcode of Life Data Systems and to the National Center for Biotechnology Information's GenBank library. According to Mitchell Eaton, who led the research, technologies to support rapid or automated DNA barcoding have yet to be developed but the first step is for scientists to build a catalog of barcodes.

"This is not something where you can wave a scanner over a piece of meat in an airport to know the animal's identity, that kind of technology is well into the future."

According to the researchers, enforcing illegal wildlife trafficking is not the only potential use of DNA barcodes. The codes also can help scientist gather data on diversity in ecosystems, invasive species, pathogens in food supplies and the impact of human hunting on forest wildlife.